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Publication numberUS3141660 A
Publication typeGrant
Publication dateJul 21, 1964
Filing dateMar 8, 1961
Priority dateMar 8, 1961
Publication numberUS 3141660 A, US 3141660A, US-A-3141660, US3141660 A, US3141660A
InventorsFirstbrook Clarke John, Smith Simpson Ernest
Original AssigneeWoodhead Monroe Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Coil springs
US 3141660 A
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Description  (OCR text may contain errors)

July 21, 1964 J. F. CLARKE ETAL. 3,141,660

United States Patent O 3,141,660 COIL SPRINGS .lohn Firstbrook Clarke and Ernest Smith Simpson,

(lssett, England, assignors to Woodhead Monroe Limited, Ossett, England, a British company Filed Mar. 8, 1961, Ser. No. 94,191 l Claim. (Cl. 267-60) This invention relates to coil springs.

For many suspension purposes there is a need of a variable rate coil spring and hitherto proposals have been made for providing springs of variable pitch between the coils, the arrangement being such that as the spring deflects it will become progressively coil bound thereby raising the rate of deection. However, springs of the form indicated are subject to certain disadvantages. In the rst place they are diicult to manufacture because for full eiciency the pitch variation must be held to very close limits and secondly when they are coil bound the inevitable rubbing between the coils results in surface damage which weakens the spring and shortens its working life. Furthermore coil to coil metallic contact creates objectionable noise.

It is the chief object of the present invention to provide for a variable rate coil spring which will not be subjected to the disadvantage indicated and in accordance therewith it is proposed to insert between a preselected number of coils of a coil spring a helical rib of rubber, plastic or other material. Conveniently, the rib may be of tapering section or of progressively decreasing or increasing thickness so that as a spring to which such strip is applied is deflected the coils will be progressively locked in turn. By suitable dimensioning of the strip it will be possible to provide a completely progressive spring rate or one, two, three or more changes of rate at given deflections of the spring.

In order that the said invention may be clearly understood and readily carried into effect the same will be hereinafter more fully described with reference to the accompanying drawing which illustrates one embodiment by way of example.

Referring now to the drawing denotes a conventional coil spring while 11 denotes a moulding of rubber or plastic material comprising a sleeve of bellows like formation having an external helical rib 12 which is of progressively tapering thickness. In the embodiment illustrated the moulding does not extend over the full length of the spring so that the coils designated a will comprise what may be termed full deflection coils which will function in a perfectly normal manner. It will be appreciated however that those coils of the spring between which the rib 12 is present will upon deflection or compression of the spring be locked up or rendered inactive so that effectively the rate of the spring will be varied. By virtue of the progressive tapering of the rib as shown the coils between which said rib is present will be locked up progressively. While tapering of the rib is advantageous such a feature is not however essential and said rib may well be of constant thickness throughout its length.

It may be mentioned here that with an arrangement such as is illustrated in the drawing it may be necessary "ice to provide some means for maintaining the moulding in position within the spring.

As an alternative it may be feasible to provide a sleeve like moulding of rubber or plastic material so dimensioned as to be capable of being applied over a coiled spring to sheath the latter for a preselected portion of its length and in such a case the helical rib would be formed internally of such sleeve like moulding so as to project between the spring coils.

Instead of either of the arrangements indicated above it may be feasible to introduce a helical rib between a predetermined number of coils of a spring and to retain such rib in the required position by means of two tubular elements or equivalent retaining means which are arranged concentrically on an end cap applied to the spring, one of such elements being adapted to project into the spring coaXially therewith while the other surrounds said spring. Again in place of such retaining means it may be feasible to mould, bond or otherwise attach the rib to the selected coils on one side of the latter, or alternatively the helical rib might be of some elastic material which is bonded to adjacent coils so that in the free position of the spring it will be under tension while on deliection of the spring it will be subjected to compression until it is the equivalent of a solid rib which will render the particular spring coils inactive.

In yet another embodiment a helical rib may be provided between the coils of a variable pitch spring, such rib being of either tapering or constant section.

It may be mentioned here that depending upon the particular mode of application the rib for insertion between the coils of any selected spring may be of rubber, plastic, or any other material which will withstand the frictional Wear satisfactorily and give adequate fatigue life.

Whichever way the helical rib is located in the spring it can be designed and made to ensure that any preselected number of coils will be rendered ineffective at any particular deflection of the spring. Thus it is possible to provide either a completely progressive variable rate spring or alternatively one, two, three or more changes of rate at given deliections.

We claim:

A variable rate spring comprising a constant rate coil spring and a substantially cylindrical element concentrically disposed with respect to said coil spring, said cylindrical element being provided with a helical rib adapted to be interposed between a preselected number of convolutions of said coil spring, said helical rib having a progressively tapered axial thickness and being operable to preclude the movement of certain of said convolutions upon the application of a predetermined force on said coil spring.

References Cited in the file of this patent UNITED STATES PATENTS 1,404,464 Meyer lan. 24, 1922 2,344,858 Farmer Mar. 28, 1942 2,661,206 Gregoire Dec. l, 1953 2,703,234 Tapp Mar. 1, 1955 2,832,587 Robert Apr. 29, 1958

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1404464 *Dec 13, 1920Jan 24, 1922Meyer Adolph FSpring
US2344858 *Mar 28, 1942Mar 21, 1944Westinghouse Air Brake CoBrake cylinder device
US2661206 *Mar 30, 1948Dec 1, 1953Albert Gregoire JeanSuspension device for vehicles
US2703234 *Jan 2, 1953Mar 1, 1955Tapp Damon LMeans for restoring the strength to weakened coil springs
US2832587 *Jun 6, 1955Apr 29, 1958Universal Air Lift IncSpring booster assemblies
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3861661 *Sep 12, 1973Jan 21, 1975Nissan MotorCompression spring assembly
US4033644 *Jul 19, 1976Jul 5, 1977Ford Motor CompanyMethod for preloading bearing
US4475725 *Dec 9, 1982Oct 9, 1984Volkswagenwerk AgElastic support for helical springs
US4614333 *Aug 16, 1985Sep 30, 1986Gaylord James KDevices for automotive vehicle coil springs
US4712778 *Dec 21, 1981Dec 15, 1987North American Philips CorporationHelical spring holder assembly
US4728087 *Feb 4, 1986Mar 1, 1988Multikunst Design ApsAnchoring arrangement for heavy coil springs, primarily in coil spring carried playground devices
US4923182 *Jun 9, 1988May 8, 1990Webley & Scott LimitedSpring energized air guns
US7213802 *Dec 27, 2002May 8, 2007Neturen Co., Ltd.Closed end type coiled spring with reduced initial deflection
US7270320 *Jul 30, 2003Sep 18, 2007Andreas Stihl Ag & Co. KgAntivibration element
US7527252 *Dec 16, 2005May 5, 2009Yamaha Hatsudoki Kabushiki KaishaSpring spacer for a spring
US7677540 *Apr 2, 2004Mar 16, 2010Duval Eugene FDual pulley constant force mechanism
US7992849 *Sep 21, 2005Aug 9, 2011Thomas SugarAdjustable stiffness jack spring actuator
US8172208 *Nov 6, 2008May 8, 2012Environmental Container SystemsVariable spring rate shock mount having a replaceable core
US8322695Feb 3, 2011Dec 4, 2012Thomas SugarAdjustable stiffness Jack Spring actuator
US8511658 *Apr 21, 2008Aug 20, 2013Hilti AktiengesellschaftVibrating hand-held power tool
CN102187113BOct 29, 2009May 15, 2013株式会社F.泰克Anti-vibration damper for coil spring
DE1282361B *Jul 15, 1967Nov 7, 1968Licentia GmbhZylindrische Schraubenfeder mit progressiver Federcharakteristik zur Verwendung in elektromagnetischen Vibratoren
DE2924135A1 *Jun 15, 1979Jan 3, 1980Mo Mash Z Im KalininaHydraulische axialkolbenmaschine
DE2942135A1 *Oct 18, 1979Apr 30, 1981Volkswagenwerk AgUnterlage aus elastischem material fuer schraubenfedern einer kraftfahrzeug-federung
WO2012139782A1 *Jan 30, 2012Oct 18, 2012Thyssenkrupp Bilstein Suspension GmbhBearing arrangement for a spring of a vehicle chassis
Classifications
U.S. Classification267/166
International ClassificationF16F1/13, F16F1/04
Cooperative ClassificationF16F1/13
European ClassificationF16F1/13